noladin-ether and anandamide

Topics: Amides; Amidohydrolases; Amines; Animals; Arachidonic Acids; Binding Sites; Cannabinoid Receptor Modulators; Drug Design; Endocannabinoids; Esters; Ethers; Glycerides; Humans; Ligands; Monoacylglycerol Lipases; Polyunsaturated Alkamides; Receptors, Cannabinoid

In the CA1 region of the rat hippocampus, metabotropic glutamate receptor-5 (mGluR5) and cannabinoid-1 receptors (CB1Rs) are believed to participate in long-term synaptic depression (LTD). How mGluRs and CB1Rs interact to promote LTD remains uncertain. In this study, we examined LTD induced by CB1R agonists, mGluR5 agonists, and low-frequency electrical stimulation (LFS) of the Schaffer collateral pathway. Synthetic CB1R agonists induced robust LTD that was mimicked by the endocannabinoid (EC), noladin ether (NLDE), but not by anandamide. 2-Arachidonylglycerol (2AG) produced only a small degree of LTD. The selective mGluR5 agonist, namely (RS)-2-chloro-5-hydroxyphenylglycine (CHPG), also induced robust LTD, and CHPG and NLDE occluded each other's effects. Similarly, CHPG and NLDE occluded LFS-induced LTD, and LTD resulting from all three treatments was blocked by a CB1R antagonist. CHPG-LTD and NLDE-LTD were insensitive to N-methyl-D-aspartate receptor (NMDAR) block, even though LFS-LTD requires NMDARs. LTD induced by LFS or CHPG, but not NLDE-LTD, was blocked by a selective mGluR5 antagonist. (RS)-3,5-dihydroxyphenylglycine (DHPG), a less selective group I mGluR agonist, also induced LTD, but its effects were not blocked by mGluR5 or CB1R antagonists. Furthermore, DHPG-LTD was additive with LFS-LTD and CHGP-LTD. These results suggest that NMDARs, mGluR5, and CB1Rs participate in a cascade that underlies LFS-LTD and that release of an EC and CB1R activation occur downstream of NMDARs and mGluR5. Furthermore, DHPG induces a form of LTD that differs mechanistically from LFS-induced depression.

Topics: Animals; Arachidonic Acids; Cannabinoid Receptor Modulators; Endocannabinoids; Excitatory Amino Acid Agonists; Excitatory Amino Acid Antagonists; Excitatory Postsynaptic Potentials; Glycerides; Glycine; Hippocampus; Long-Term Synaptic Depression; Neurons; Phenylacetates; Polyunsaturated Alkamides; Rats; Rats, Sprague-Dawley; Receptor, Metabotropic Glutamate 5; Receptors, Metabotropic Glutamate; Receptors, N-Methyl-D-Aspartate; Synaptic Transmission

We report the synthesis of new chemical probes (1a,b, 2a-c, 3a-c) based on the structure of the main endocannabinoids for their use in biological systems directly or via click chemistry. As proof of concept, 2-arachidonyl glyceryl ether based biotinylated 3b enables direct visualization of CB(1) receptor in cells. These results represent the starting point for the development of advanced small molecule chemical probes able to generate valuable information about the cannabinoid receptors.

Topics: Alkenes; Arachidonic Acids; Benzophenones; Binding, Competitive; Biotin; Cannabinoid Receptor Modulators; Cell Line; Click Chemistry; Endocannabinoids; Glycerides; Humans; Ligands; Molecular Probes; Polyunsaturated Alkamides; Radioligand Assay; Receptor, Cannabinoid, CB1; Receptor, Cannabinoid, CB2; Structure-Activity Relationship

The endocannabinoid system functions through two well characterized receptor systems, the CB1 and CB2 receptors. Work by a number of groups in recent years has provided evidence that the system is more complicated and additional receptor types should exist to explain ligand activity in a number of physiological processes.. Cells transfected with the human cDNA for GPR55 were tested for their ability to bind and to mediate GTPgammaS binding by cannabinoid ligands. Using an antibody and peptide blocking approach, the nature of the G-protein coupling was determined and further demonstrated by measuring activity of downstream signalling pathways.. We demonstrate that GPR55 binds to and is activated by the cannabinoid ligand CP55940. In addition endocannabinoids including anandamide and virodhamine activate GTPgammaS binding via GPR55 with nM potencies. Ligands such as cannabidiol and abnormal cannabidiol which exhibit no CB1 or CB2 activity and are believed to function at a novel cannabinoid receptor, also showed activity at GPR55. GPR55 couples to Galpha13 and can mediate activation of rhoA, cdc42 and rac1.. These data suggest that GPR55 is a novel cannabinoid receptor, and its ligand profile with respect to CB1 and CB2 described here will permit delineation of its physiological function(s).

Topics: Amino Acid Sequence; Animals; Arachidonic Acids; Binding Sites; Binding, Competitive; Cannabidiol; Cannabinoids; Cell Line; Cloning, Molecular; Cyclohexanols; Down-Regulation; Endocannabinoids; Guanosine 5'-O-(3-Thiotriphosphate); Humans; Ligands; Mice; Molecular Sequence Data; Organ Specificity; Polymerase Chain Reaction; Polyunsaturated Alkamides; Rats; Receptors, Cannabinoid; Receptors, G-Protein-Coupled; RNA, Messenger; Signal Transduction; Structure-Activity Relationship

A sensitive and specific liquid chromatography-tandem mass spectrometry (LC-MS/MS) method is described for the simultaneous identification and quantification of eight endocannabinoid (EC) or related "entourage" compounds in rat brain tissue. Analytes were extracted and purified from rat brain tissue using an ethyl acetate/hexane solvent extraction, followed by a solid phase extraction (SPE) protocol. Chromatographic separation was achieved using a gradient elution, with a mobile phase of acetonitrile, formic acid, and ammonium acetate, at pH 3.6. A Thermo Hypersil C8 HyPurity Advance column (100x2.1 mm i.d., 3 microm) was used with a flow rate of 0.3 ml/min). Anandamide (AEA), 2-arachidonyl glycerol (2-AG), 2-arachidonylglyceryl ether (noladin ether), O-arachidonyl ethanolamide (virodhamine), 2-linoleoyl glycerol (2-LG), arachidonyl glycine, oleoyl ethanolamide (OEA), and palmitoyl ethanolamide (PEA) were quantified by positive ion tandem electrospray ionization mass spectrometry. Internal standards were deuterated AEA, deuterated 2-AG, and heptadecanoyl ethanolamide (HEA). Linearity was proven over the range of 25 fmol to 250 pmol, with a limit of detection of 25 fmol on column for all analytes except 2-AG, noladin ether, and 2-LG (250 fmol). This corresponded to a limit of quantification in biological tissue of 10 pmol/g for all analytes except 2-AG (100 pmol/g). Intra- and interday precision in biological tissue was routinely approximately 20% or lower, and accuracy was between 65% and 155%. This method was used to quantitatively profile regional differences in nine discrete rat brain regions for AEA, 2-AG, 2-LG, OEA, PEA, noladin ether, virodhamine, and arachidonyl glycine.

Topics: Animals; Arachidonic Acids; Brain Chemistry; Cannabinoid Receptor Modulators; Cannabinoids; Chromatography, Liquid; Endocannabinoids; Glycerides; Glycine; Male; Oleic Acids; Polyunsaturated Alkamides; Rats; Rats, Sprague-Dawley; Reproducibility of Results; Spectrometry, Mass, Electrospray Ionization; Tandem Mass Spectrometry

The endocannabinoids, N-arachidonoylethanolamide (anandamide) and 2-arachidonoylglycerol (2-AG) are rapidly degraded by fatty acid amide hydrolase (FAAH) and monoacylglycerol lipase (MGL). Whilst these lipid mediators are known to modulate vascular tone, the extent to which they are inactivated via local metabolism in the vasculature remains unclear.. In rat isolated small mesenteric arteries, the regulatory role of FAAH, MGL and cyclooxygenase (COX) in relaxant responses to anandamide and 2-AG was evaluated by using inhibitors of these enzymes. Relaxations to non-hydrolysable analogues of endocannabinoids and arachidonic acid were also examined.. Relaxation to anandamide but not 2-AG was potentiated by the selective FAAH inhibitor, URB597 (1 microM). In contrast, MAFP (10 microM; an inhibitor of FAAH and MGL) enhanced responses to both anandamide and 2-AG. Inhibition of COX-1 by indomethacin (10 microM) potentiated relaxations to 2-AG, whereas inhibition of COX-2 by nimesulide (10 microM) potentiated anandamide-induced relaxation. With the exception of MAFP, effects of FAAH and COX inhibitors were dependent on the endothelium. Relaxation to methanandamide and noladin ether, the non-hydrolysable analogues of anandamide and 2-AG respectively, were insensitive to the enzyme inhibitors.. This study shows that local activity of FAAH, MGL and COX, which is present largely in the endothelium, limits the vasodilator action of endocannabinoids in rat small mesenteric arteries. Despite the differential roles played by these enzymes on relaxation to anandamide versus 2-AG, our results suggest that inhibitors of these enzymes enhance the vascular impact of endocannabinoids.

Topics: Amidohydrolases; Animals; Arachidonic Acids; Benzamides; Cannabinoid Receptor Modulators; Carbamates; Cyclooxygenase 1; Cyclooxygenase 2; Cyclooxygenase Inhibitors; Dose-Response Relationship, Drug; Endocannabinoids; Endothelium, Vascular; Enzyme Inhibitors; Glycerides; Hydrolases; In Vitro Techniques; Lectins; Lectins, C-Type; Male; Membrane Proteins; Mesenteric Artery, Superior; Organophosphonates; Polyunsaturated Alkamides; Prostaglandin-Endoperoxide Synthases; Rats; Rats, Wistar; Receptors, Cell Surface; Vasodilation; Vasodilator Agents

In the globus pallidus, cannabinoid CB(1) receptors are localized pre-synaptically on GABAergic neurons. We assessed the influence of the endocannabinoids, anandamide, 2-arachidonoyl-glycerol (2-AG) and noladin ether, on the uptake of [(3)H]-GABA in pallidal slices from rat. Both 2-AG and noladin ether increased [(3)H]-GABA uptake (by 40.8 +/- 8.0% and 38.4 +/- 12.5%). The effect of 2-AG was blocked by the cannabinoid CB(1) receptor antagonist AM 251. In contrast, neither anandamide nor the agonist WIN 55,212-2 had an effect on [(3)H]-GABA uptake. Different roles might be played by different endocannabinoids, both physiologically and in basal ganglia disorders, such as Parkinson's disease.

Topics: Animals; Arachidonic Acids; Binding, Competitive; Cannabinoid Receptor Modulators; Endocannabinoids; gamma-Aminobutyric Acid; Globus Pallidus; Glycerides; In Vitro Techniques; Male; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Rats; Rats, Sprague-Dawley; Receptor, Cannabinoid, CB1; Tritium

As persistent behavioural changes, such as increased anxiety-related behaviours, can be predicted based on the phenomenon of psychostimulant-induced neuronal plasticity, the time course (3-, 5- and 10-day time points) of the effects of both a single and repeated (daily for 7 days) i.p. administrations of cocaine (COC) and methamphetamine (MA) on anxiety-related behavioural symptoms in the elevated plus-maze test were examined in mice. Furthermore, based on the reported interactions between brain dopamine versus cannabinoid (CB) receptors and the contribution of CB receptors to the occurrence of persistent anxiety-related behavioural symptoms, the interactions of the agonist CP 55940 (CP) and the endogenous ligands anandamide (arachidonylethanolamide: AEA), 2-arachidonylglycerol (ARA), N-arachidonyldopamine (NADA), noladin ether (NL), and virodhamine (VA) with the COC- or MA-induced anxiety-related behaviours were also studied. In both an acute experiment using a single COC (30 mg/kg) or MA (4 mg/kg) dose and a chronic experiment using repeated COC (15 mg/kg) or MA (2 mg/kg) doses, anxiety-related behavioural symptoms were observed similarly at 3- and 5-day time points, but disappeared at the 10-day time point. Among the CB ligands, the agonists CP, AEA, ARA, NADA, and NL provided strong protective effects against each parameter at 3- and 5-day time points. Therefore, it was concluded that both COC and MA caused persistent anxiety-related behavioural symptoms following both a single and repeated treatments. Since these anxiogenic effects were attenuated by the endogenous CB agonists, the involvement of brain CB receptors was suspected.

Topics: Analysis of Variance; Animals; Anxiety; Arachidonic Acids; Behavior, Animal; Cannabinoids; Cocaine; Cyclohexanols; Dopamine; Dose-Response Relationship, Drug; Drug Interactions; Endocannabinoids; Glycerides; Injections, Intraperitoneal; Male; Maze Learning; Methamphetamine; Mice; Mice, Inbred ICR; Polyunsaturated Alkamides; Receptor, Cannabinoid, CB1; Time Factors

Depolarization-induced suppression of excitation and inhibition (DSE and DSI) appear to be important forms of short-term retrograde neuronal plasticity involving endocannabinoids (eCB) and the activation of presynaptic cannabinoid CB1 receptors. We report here that CB1-dependent DSE can be elicited from autaptic cultures of excitatory mouse hippocampal neurones. DSE in autaptic cultures is both more robust and elicited with a more physiologically relevant stimulus than has been thus far reported for conventional hippocampal cultures. An additional requirement for autaptic DSE is filled internal calcium stores. Pharmacological experiments favour a role for 2-arachidonyl glycerol (2-AG) rather than arachidonyl ethanolamide (AEA) or noladin ether as the relevant endocannabinoid to elicit DSE. In particular, the latter two compounds fail to reversibly inhibit EPSCs, a quality inconsistent with the role of bona fide eCB mediating DSE. Delta9-Tetrahydrocannabinol (delta9-THC) fails to inhibit EPSCs, yet readily occludes both DSE and EPSC inhibition by a synthetic CB1 agonist, WIN 55212-2. With long-term exposure (approximately 18 h), delta9-THC also desensitizes CB1 receptors. Lastly, a functional endocannabinoid transporter is necessary for the expression of DSE.

Topics: Animals; Arachidonic Acids; Benzoxazines; Calcium; Cannabinoid Receptor Modulators; Cells, Cultured; Dronabinol; Endocannabinoids; Excitatory Postsynaptic Potentials; Glutamic Acid; Glycerides; Hippocampus; Mice; Mice, Inbred C57BL; Morpholines; Naphthalenes; Neuronal Plasticity; Neurons; Nitric Oxide; Patch-Clamp Techniques; Polyunsaturated Alkamides; Receptor, Cannabinoid, CB1

Endocannabinoids may serve as retrograde messengers to inhibit neurotransmitter release during depolarization-induced suppression of inhibition (DSI) or excitation (DSE). We therefore tested whether endocannabinoids inhibit N-type voltage-dependent Ca2+ channels by activating G(i/o)-protein-coupled CB1 cannabinoid receptors (CB1R)--a possible mechanism underlying DSI/DSE. Three putative endocannabinoids [2-arachidonylglycerol (2-AG), 2-arachidonyl glycerol ether (2-AGE), and anandamide (AEA)] and the cannabimimetic aminoalkylindole WIN 55,212-2 (WIN) inhibited whole-cell Ca2+ currents in rat sympathetic neurons previously injected with cDNA encoding a human CB1R. Agonist-mediated Ca2+ current inhibition was blocked by a selective CB1R antagonist [SR141716A, N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboximide hydrochloride] and pertussis toxin (PTX) pretreatment. The rank order of potency was WIN (IC50=2 nM)>2-AGE (350 nM) approximately 2-AG (480 nM)>AEA (approximately 3 microM), with each agonist displaying similar efficacy (approximately 50% maximal inhibition). Increasing CB1R expression level significantly enhanced AEA potency. AEA (10 microM) also inhibited Ca2+ channels in a voltage-independent, CB1R-independent, and PTX-insensitive manner, whereas 2-AG and 2-AGE were devoid of this activity. All three endocannabinoids activated G-protein-coupled inwardly rectifying potassium (GIRK) channels, GIRK1/4, heterologously expressed in sympathetic neurons. These results suggest a mechanism by which endocannibinoids might influence presynaptic function.

Topics: Animals; Arachidonic Acids; Benzoxazines; Calcium; Calcium Channel Blockers; Calcium Channels, N-Type; Cannabinoids; Dose-Response Relationship, Drug; Endocannabinoids; G Protein-Coupled Inwardly-Rectifying Potassium Channels; Glycerides; GTP-Binding Proteins; Humans; In Vitro Techniques; Male; Morpholines; Naphthalenes; Neurons; Polyunsaturated Alkamides; Potassium Channels; Potassium Channels, Inwardly Rectifying; Rats; Rats, Wistar; Receptor, Cannabinoid, CB1

The endogenous cannabinoids N-arachidonylethanolamide (AEA) and 2-arachidonylglycerol (2-AG) are known to decrease intraocular pressure (IOP). Recently, a novel putative endogenous cannabinoid, noladin ether, was isolated in porcine and rat brains. In the present study, both the degradation of endogenous cannabinoids in ocular tissues and the effect on IOP of 2-AG and noladin ether were compared.. The rates of enzymatic degradation for AEA, 2-AG, and noladin ether were determined in bovine cornea and iris-ciliary body homogenates. 2-AG and noladin ether were dissolved in either hydroxypropyl-beta-cyclodextrin (HP-beta-CD) or propylene glycol and administered unilaterally to the rabbit eye. IOPs were measured in the treated and untreated eyes. The CB1 receptor antagonist AM251 was administered topically 15 minutes before the cannabinoids to investigate whether CB1 receptors mediate the effect on IOP produced by 2-AG and noladin ether.. Noladin ether degraded more slowly than either 2-AG or AEA in the iris-ciliary body and cornea homogenates. The effect on IOP of 2-AG was biphasic (i.e., an initial increase in IOP followed by a reduction in the treated eye). Noladin ether decreased IOP immediately after topical administration, and no initial IOP increase was observed in the treated eye. The CB1 receptor antagonist AM251 (25 micro g) blocked the effect on IOP of noladin ether but did not affect the action of 2-AG.. Topical administration of the novel putative endogenous cannabinoid noladin ether decreased IOP in rabbits. This IOP reduction was most probably mediated through the CB1 receptor. The effect on IOP of noladin ether differed from those of the known endogenous cannabinoids AEA and 2-AG, probably because of its more stable chemical structure.

Topics: Animals; Arachidonic Acids; Cannabinoid Receptor Modulators; Cattle; Ciliary Body; Cornea; Endocannabinoids; Enzyme Stability; Female; Glycerides; Intraocular Pressure; Iris; Male; Piperidines; Polyunsaturated Alkamides; Pyrazoles; Rabbits; Receptors, Cannabinoid; Receptors, Drug

Cannabinoid receptor agonists including anandamide and noladin either have recently been suggested to exhibit neuroprotective properties. The amyloid-beta (Abeta) peptide is thought to be responsible for the neurodegenerative changes associated with Alzheimer's disease pathology. This study characterizes the effects of anandamide and noladin ether on the neurotoxicity of Abeta in differentiated human teratocarcinoma cell line, Ntera 2/cl-D1 neurons. Anandamide and noladin ether, at nanomolar concentrations, showed concentration dependent inhibition of Abeta toxicity. A CB(1) cannabinoid receptor antagonist, AM251, prevented the protective effects of anandamide and noladin ether. The mitogen activated protein kinase (MAPK) pathway inhibitor PD98059 also prevented the protective effects of cannabinoids and corticotrophin-releasing hormone. These results suggest that activation of the MAPK pathway by either cannabinoids or corticotrophin-releasing hormone could be used to prevent Abeta peptide induced neurodegeneration.

Topics: Amyloid beta-Peptides; Arachidonic Acids; Cannabinoids; Corticotropin-Releasing Hormone; Endocannabinoids; Enzyme Inhibitors; Flavonoids; Glycerides; Humans; Mitogen-Activated Protein Kinases; Nervous System Diseases; Neurons; Neuroprotective Agents; Neurotoxins; Oxidation-Reduction; Peptide Fragments; Polyunsaturated Alkamides; Receptors, Cannabinoid; Receptors, Drug